"In the days following my release, I have learned bit by bit that there have been hundreds of people -- brave, determined, big-hearted people -- all over the world working on my release. I had no idea when I was in prison that so much effort was being made on my behalf," he said from his mother's home Wednesday.

Curtis said he has been touched and moved family, friends and strangers welcoming him back to Massachusetts.

""I suddenly remember how good the American people are and what kindness they have in their hearts," he said.

He said he's looking forward to reconnecting with loved ones.

"I am so grateful that you are expressing all this interest in me, but I have to bond with my mother and family now," Curtis said.

He said he was indebted to the United States officials who worked on his case, and the government of Qatar for intervening.

"I'm overwhelmed with relief that this day has come and my son is standing beside me," Nancy Curtis said. "But this is a sober occasion because of the events of the past week. My heart goes out to the other families who are suffering."

Last week, journalist James Foley, who also was kidnapped in 2012 while covering the Syrian uprising, was killed. The Islamic State group posted a Web video showing his beheading.

The extremists said they killed the Rochester, New Hampshire, resident in retaliation for U.S. airstrikes targeting Islamic State positions in northern Iraq.

Curtis' mother said she was "overwhelmed with relief" that her son had been returned to her. "But this is a sober occasion because of the events of the past week," she said. "My heart goes out to the other families who are suffering."

U.S. freelance journalist, Austin Tice of Houston, disappeared in Syria in August 2012. He is believed to be held by the Syrian government.